I didn't test your plugin yet. But I will test it in the near future. Now you guys have good review for this plugin. Moreover, it's nice to see that you have added two screenshots under that plugin. I vouch for your effort. Good job mate!
Not bad Wordpress plugin.
But please do not use "red" or "blue" colours inside your plugin, it makes me feel sick sometimes.
You can use two columns for showing your tool, a left side shows "Country" and right side displays "Keyword Input".